WO1998018300A2 - Accelerateur de faisceau electronique a onde rotative - Google Patents

Accelerateur de faisceau electronique a onde rotative Download PDF

Info

Publication number
WO1998018300A2
WO1998018300A2 PCT/US1997/018183 US9718183W WO9818300A2 WO 1998018300 A2 WO1998018300 A2 WO 1998018300A2 US 9718183 W US9718183 W US 9718183W WO 9818300 A2 WO9818300 A2 WO 9818300A2
Authority
WO
WIPO (PCT)
Prior art keywords
resonator
rotating
magnetic field
frequency
electron beam
Prior art date
Application number
PCT/US1997/018183
Other languages
English (en)
Other versions
WO1998018300A3 (fr
Inventor
Jose E. Velazco
Original Assignee
Microwave Technologies Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Microwave Technologies Inc. filed Critical Microwave Technologies Inc.
Priority to AU48962/97A priority Critical patent/AU4896297A/en
Publication of WO1998018300A2 publication Critical patent/WO1998018300A2/fr
Publication of WO1998018300A3 publication Critical patent/WO1998018300A3/fr

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H15/00—Methods or devices for acceleration of charged particles not otherwise provided for, e.g. wakefield accelerators
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H7/00—Details of devices of the types covered by groups H05H9/00, H05H11/00, H05H13/00
    • H05H7/14—Vacuum chambers
    • H05H7/16—Vacuum chambers of the waveguide type
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H7/00—Details of devices of the types covered by groups H05H9/00, H05H11/00, H05H13/00
    • H05H7/14—Vacuum chambers
    • H05H7/18—Cavities; Resonators

Definitions

  • This invention relates in general to the field of high energy charged particle beam-wave accelerators which operate at relativistic energies, e.g., 100 keV to 100 MeV, and more particularly, to improvements in linear and cyclotron high energy charged particle beam- wave accelerators.
  • Microwave linear accelerators which use oscillating electric fields to accelerate charged particles (such as electrons) have been used for years as a way to overcome the maximum voltage limitations of static accelerator fields.
  • a stream of electrons is typically passed through a set of microwave cavities containing oscillating electric fields. These oscillating electric fields accelerate the electron stream. Because the accelerating electric fields in these cavities are oscillating periodically, they are only in the correct direction for half the microwave period. To ensure that the fields accelerate rather than decelerate the electron stream, the cavities containing these fields are made short enough so that an electron can completely traverse the length of the cavity before the cavity field reverses to the unwanted direction.
  • Such known microwave linear accelerators have certain problems.
  • the short microwave cavity length limits the acceleration force that can be applied to the electrons. This problem has been dealt with in the past by providing additional cavities phased such that the accelerated electrons will find the electric field in the correct direction during the electrons' transit through each successive cavity. This solution increases the amount of acceleration force, but also increases the size and complexity of the linear accelerator.
  • Another problem with such known microwave linear accelerators relates to their efficiency.
  • the electron source e.g., an electron gun
  • the electron source typically produces a continuous stream of electrons.
  • Electrons not properly timed will not be correctly accelerated, and will eventually hit the cavity walls.
  • cyclotron accelerator Another type of accelerator is known as a "cyclotron accelerator.”
  • cyclotron accelerator When people hear the term “cyclotron” they often think of huge systems spanning several miles used to generate extremely high energy particles for "smashing atoms.” However, not all cyclotron accelerators are huge.
  • a “cyclotron” is a circular particle accelerator in which charged subatomic particles generated at a central source are accelerated spirally outward in a plane perpendicular to a fixed magnetic field by an alternating electric field.
  • cyclotron accelerators utilize transverse- electric (TE) electromagnetic modes to produce acceleration of an electron beam immersed in an axial focusing magnetic field.
  • TE transverse- electric
  • Such cyclotron wave accelerators accelerate a charged particle in the direction of power flow of the electromagnetic wave energy in a manner such that the frequency of the wave as seen by the particle is Doppler shifted to a lower value.
  • the decrease in frequency as seen by the particle is exactly the amount necessary to compensate for the lower cyclotron frequency that results from the relativistic increase in particle mass.
  • ⁇ c is the relativistic cyclotron frequency and ⁇ is the angular frequency of the wave.
  • a traveling wave cyclotron accelerator may, for example, use a cylindrical waveguide containing a circularly polarized transverse- electric traveling mode microwave wave as the means to produce beam acceleration.
  • One limitation that such traveling wave cyclotron accelerators present is that, for a reasonable amount of input microwave power, the microwave electric field inside the waveguide is relatively weak. These fields are not strong enough to produce rapid acceleration of the particles ⁇ and thus require a long interaction to produce substantial acceleration of the particle beam.
  • one example cyclotron accelerator using a 70 cm-long waveguide operating in a TE ⁇ mode has been able to accelerate an electron beam up to 360 keV but requires 5 megawatts (that is 5 million watts) of microwave power. See Hirshfield, J.
  • Cyclotron accelerators have been constructed using a microwave cavity employing a short cylindrical resonator holding a TE,, , circularly polarized mode for particle acceleration. These cavity accelerators are much more compact than their traveling wave counterparts.
  • one drawback of these cavities is that their dimensions (cavity radius and length) are both frequency dependent. That is to say, at a given frequency of operation, the cavity length becomes rather short if a reasonable cavity cross-section (radius) is to be obtained. It becomes very difficult to construct suitable magnetic coils around the short cavity to provide the required non-uniform up- tapered axial magnetic field profile to maintain cyclotron resonance throughout the beam path.
  • the present invention provides a technique for producing an accelerated charged particle beam that involves injecting charged particles into a resonant rotating microwave field exhibiting a transverse magnetic rotating wave mode having no axial periodicity; and using the rotating microwave field to both accelerate and spiral the particles to produce an accelerated beam.
  • a rotating wave electron beam accelerator provided in accordance with the present invention includes a microwave resonator and a particle generator coupled to the resonator.
  • the particle generator injects charged particles into the resonator.
  • a radio frequency source coupled to the resonator induces, within the resonator, a resonant rotating microwave field exhibiting a transverse magnetic rotating wave mode having no axial periodicity.
  • the rotating microwave field has both magnetic and electric field components.
  • the rotating microwave magnetic field component causes the particles to spiral along a helical path, and the microwave electric field component accelerates the particles.
  • the resonator has a length that is independent of the frequency of the resonant microwave field - and the resonator is radially dimensioned to determine the frequency of the resonant microwave field.
  • the resulting overall device can be very efficient and compact, and has numerous applications for example, as an electron source, and as an x-ray source in medicine, industry and defense.
  • a rotating-wave accelerator that provides a continuous stream of monochromatic charged particles employing a relatively short (e.g., TMj ⁇ o) rotating mode cavity with a suitably up-tapered axial focusing magnetic field.
  • a rotating-wave accelerator using a transverse-magnetic rotating wave mode, TMi 10 that allows the cavity frequency to be independent of cavity length.
  • a rotating-wave accelerator using a relatively unknown rotating (or circularly polarized) type of microwave field which has constant, but rotating fields, to eliminate the need for bunched beams and short cavities while allowing the use of a spiraling moving beam.
  • Figure 1 is a schematic illustration of an example embodiment of a rotating-wave accelerator in accordance with the present invention
  • Figures la and lb show front and side views respectively of an example embodiment of a rotating-wave accelerator provided in accordance with the present invention
  • Figure 2 shows an example profile of the axial magnetic field along the beam path to provide gyroresonance for substantial beam acceleration and for beam extraction
  • Figure 3 shows an example of the electric and magnetic field lines of the rotating TM ⁇ o mode
  • Figure 4 shows an example electron orbit with respect to the fields of a TM 1 10 rotating mode under gyroresonance
  • Figure 5 shows an example electron orbit along the z axis under gyroresonance where one can note that the electron radial displacement gradually increases as it moves along the z axis;
  • Figure 6 shows an example plot of the rf electric field that an electron "sees" as a function of radial displacement
  • Figure 7 shows an example snapshot of an electron beam moving under the influence of an axial magnetic field Bz as it is accelerated by the fields of a TM, 10 rotating mode
  • Figure 8 shows the dynamics of an electron beam along the accelerating cavity of an example rotating-wave accelerator calculated on a commercial three-dimensional particle-in-cell electromagnetic code
  • Figure 9 shows an example profile for the magnetic field along the beam extractor region that provides gradual (adiabatic) magnetic decompression of the charged particle beam produced by the accelerator
  • Figure 10 shows a side view of a further example rotating wave accelerator embodiment provided in accordance with the present invention.
  • FIGS 1, 1A and IB An example embodiment of an accelerator 10 provided by the present invention is illustrated in Figures 1, 1A and IB.
  • the example embodiment rotating wave accelerator 10 uses several strategies to cope with the alternating nature of microwave fields used in linear accelerators to achieve compactness and efficiency.
  • it employs a relatively unknown rotating (or circularly polarized) type of microwave field transverse-magnetic rotating wave mode, TM 1 10 which has constant, but rotating fields.
  • This mode allows the cavity 24 frequency to be independent of cavity length; and it eliminates the need for bunched beams and short cavities while allowing the use of a spiraling moving beam.
  • the microwave magnetic fields produce the spiraling beam 100, and the microwave electric field accelerates it.
  • the accelerating structure in a normal microwave accelerator is further composed of many short cavities because of the transit time condition.
  • the Figure 1 example can use a single long cavity 24 to prepare and totally accelerate the beam to its final energy.
  • the rotating-wave accelerator in Figs. 1, 1A and IB includes a particle generating assembly 20; a cylindrical microwave resonator 24; waveguides 28, 29; a thin foil 40; a target 44; drift tubes 22, 23; a focusing magnetic system 26; coupling apertures 30, 32; a radio-frequency (rf) generator 34; a vacuum pump 38; a beam extractor 42; a compression coil 46; vacuum windows 48, 50.
  • the cylindrical cavity 24 is evacuated to a suitable low pressure, (e.g. 10" 9 Torr) by means of a suitable vacuum pump means 38.
  • Particle generating assembly 20 (which may be an electron gun) is disposed at the upstream end portion of 24a of cavity 24.
  • Particle generating assembly 20 produces and directs an electron beam 100 into cavity 24 along central beam axis 102 of accelerator 10.
  • a cut-off tubing section 22 prevents microwave energy within cavity 24 from flowing into the region of particle generating assembly 20 while permitting the electron beam 100 produced by the particle generating assembly to enter the rotating-wave accelerator region 104 within cavity 24.
  • the rotating-wave accelerating region 104 is defined within a circular cylindrical cavity 24 coaxially disposed about the central axis 102 and terminating at a downstream end portion 24b thereof by any suitable load means 40 such as a thin aluminum foil which will maintain vacuum integrity while permitting the accelerated electrons to pass therethrough.
  • Cavity 24 can be excited with circularly polarized TMi 10 rotating waves by providing a pair of 90° azimuthal space rotating coupling apertures 30, 32 in the front wall 24c of the cylindrical cavity 24.
  • the coupling apertures 30, 32 are fed via waveguides 28, 29 (see Figure IB) by a suitable rf drive system that includes an rf generator 34.
  • Power from the rf generator 34 can be fed into the input waveguide ports 28, 29 via conventional vacuum window flange assemblies 48, 50 (see Figure IB) to excite a circularly polarized TMn 0 rotating wave inside accelerator cavity 24.
  • an rf signal generator such as a klystron or magnetron can feed a 3 dB hybrid coupler with one port terminated in a matched load.
  • the coupler splits the input energy from the generator into two 90° time phased equal amplitude waves which are coupled via any conventional coupling means, e.g., waveguide into the waveguides 28, 29 via conventional vacuum window flange assemblies 48, 49 to generate a TM, , 0 rotating wave inside resonator 24.
  • any conventional coupling means e.g., waveguide into the waveguides 28, 29 via conventional vacuum window flange assemblies 48, 49 to generate a TM, , 0 rotating wave inside resonator 24.
  • the electron beam emanating from particle generating assembly 20 will assume a helical trajectory of expanding radius 36 (see Figure 7) which is a general representation of the motion.
  • a suitable magnetic field generator 26 such as, e.g., solenoid windings and associated magnetic field adjuster 110 produces an appropriate axial magnetic field profile 52 (see Figure 2).
  • the magnetic field produced by magnetic field generator 26 is adjusted to achieve "gyroresonance" (as discussed below).
  • the rapid (i.e., sudden) variation of the axial magnetic field profile at the end of the cavity from Bzm to 0, sometimes denoted as "magnetic-cusp,” can be obtained by means of extractor 42, such as, for example, a disk made out of magnetic material such as, e.g. soft iron.
  • Drift tube 23 is properly shaped so as to prevent flow of microwave energy therethrough.
  • magnetic field generator 26 include but are not limited to, solenoids, electro-magnets, super-conducting magnets and permanent magnets.
  • Accelerator cavity 24 in this example is cylindrical in geometry and operates in a transverse-magnetic rotating wave mode, TM, 10 .
  • Fig 3 shows an example cross-section of cavity 24 including electric and magnetic field lines of the TM 110 rotating mode.
  • the three mode indices: 1, 1, 0, indicate the fields dependence on the azimuthal, radial and axial coordinates of the cavity 24, respectively.
  • the first index (1) indicates the azimuthal periodicity of the mode
  • the second index (1) denotes the radial periodicity of the mode
  • the third index (0) indicates the axial periodicity of the mode. Consequently, in this mode the fields do not have axial periodicity, unlike TEi ⁇ modes, and thus are independent of the cavity 24 's length.
  • the cavity 24 's radius is the only dimension that dictates the frequency of operation of the cavity.
  • the cavity 24 's length (axial dimension), is totally frequency independent and thus can be freely adjusted.
  • Fig 9 a modification of the extractor field shown in Fig 2 is depicted which involves the gradual (adiabatic) decrease of the axial magnetic field from Bzm to Bzf.
  • This gradual reduction of the magnetic field will convert the rotating axially translating helical beam into an expanding helix which describes a conical surface.
  • the transverse velocity of the rotating beam is gradually converted into axial velocity as the radial position of the beam is also gradually enlarged from its initial value at the exit of the accelerator cavity 24.
  • the change in transverse velocity is equal to the square root of Bzf/Bzm whereas the change in radial position is proportional to the square root of Bzm/Bzf.
  • the drift tube 23 should be properly shaped to fit the conical particle beam.
  • the profiles of the axial magnetic field illustrated in Figs 2 and 9 can be implemented by any well known manner such as varying the number of turns of solenoid 26 or by independently powering a set of discrete electro-magnet coils 26 by means of a magnetic field adjuster 110.
  • An example of the magnetic field adjuster could be a set of power supplies or pulsers each designed to deliver a proper amount of current to each coil 26. If a single solenoid 26 with an axially- varying number of turns is employed, a single power supply could be used to provide the necessary current to the solenoid.
  • conventional means can be utilized such as a properly wound solenoid or discrete electro-magnet coils.
  • each coil could be driven with a different current by magnetic field adjuster 110 or the coils can be electrically connected in series and field adjusted 110 can provide a single amount of current. In the latter case, the axial distance between consecutive coils should be gradually increased so as to produce the desired (down-tapered) field profile.
  • a compact permanent magnet can be utilized to provide the field profiles shown in Figs 2 and 9. Permanent magnets are typically designed with ferromagnetic materials such as Alnico or rare earth materials such as Samarium Cobalt that can be magnetized to provide complicated magnetic field profiles. See Clark J and Leupold, H., IEEE Trans. Magn. MAG-22, 1986, pp. 1063-1065.
  • a permanent coil eliminates the need of field adjuster 110 providing an efficient and lightweight focusing system.
  • v is the particle velocity
  • e and m are, respectively, the electron's charge and mass.
  • z direction is the direction of the static magnetic field.
  • the electrons in the electron beam are injected into the accelerator 10 with an initial velocity v z in the z direction along the direction of the static magnetic field and will travel along a straight axis 102 unless they are given some velocity component perpendicular to the magnetic field. However, if they are given some perpendicular velocity, then they will orbit (or precess) around the magnetic field direction (as discussed above) in addition to the z directed motion.
  • TMi 10 rotating (or circularly polarized) microwave field as shown in Fig. 3.
  • the fields in this mode oscillate and rotate about the cavity axis at the frequency ⁇ . See J. Velazco and P. Ceperley, IEEE Trans. Microwave Theory Tech. MTT-41 (1993), pp. 330-335.
  • the TM 1 10 mode is a cutoff mode having a z directed electric field Ez which is independent of z.
  • the microwave magnetic field B interacts with the z directed velocity component of the electrons to create a perpendicular force on the electrons given by:
  • This rf magnetic field will continuously increase the perpendicular velocity of the electrons, further increasing the radius of their orbits and the diameter of the helical paths.
  • the increasingly wide helical trajectory of a single electron is shown in Fig. 5.
  • the radius of the orbital path is graphed in Fig. 6 versus distance for reasonable fields. Note that because of relativistic reasons, the helical path radius approaches a maximum limit (since the electrons radial velocity cannot exceed the speed of light).
  • the purpose of the above process is to set-up the electrons' trajectory and orbital frequency so as to allow the last set of fields to efficiently accelerate the electrons.
  • These last fields are the rotating microwave electric fields Ez, shown in Fig. 3, which are in the z direction and rotate along with the microwave magnetic fields ⁇ and because of gyroresonance they also rotate along with the particles on their orbits. They exert a force
  • Fig. 5 The trajectory of Fig. 5 is the path that a single electron in the beam moves along. However a snap shot of the beam at one instant in time would show the beam to appear as a slightly bent straight line, as shown in Fig. 7. This whole beam is at the azimuthal angle of the maximum positive microwave electric field and rotates as a whole around the axis as indicated in the drawing. Under these conditions, all the electrons forming the beam undergo equal acceleration inside cavity 24 in a dc-like fashion. Thus, at the end of cavity 24, a monochromatic helical rotating beam is obtained.
  • Figure 2 shows the profile of the axial magnetic field along the beam path necessary to provide gyroresonance for substantial beam acceleration and for beam extraction.
  • the field is carefully up-tapered from its initial value Bzo to its maximum value Bzm.
  • the degree of taper should be gradual so as to prevent the particles' axial velocity to become negative in which case beam reflection towards the particle generating assembly 20 can occur. (Alternately, one could allow the magnetic field to be constant and achieve approximate or average gyroresonance. Computer simulations have verified this to be an effective alternative for relatively short accelerators.)
  • the values of Bzo and Bzm can be found from Eq. 4 where the corresponding values of v should be replaced.
  • the electric field (rf voltage) inside cavity 24 should be properly adjusted to provide the desired beam acceleration.
  • a disk extractor 42 made out of magnetic material such as soft iron.
  • This pole disk 42 should be made thick enough to prevent saturation of the iron and with an inner diameter large enough to allow the free passage of the particle beam.
  • the helical beam is thus changed from a helical beam carrying transverse and axial velocity components to a helical beam streaming with a velocity that is purely axial.
  • a compression field For magnetic compression of the beam towards the target, a compression field can be employed.
  • the compression field is provided by compression coil 46 which is typically constructed with a short axial length and small radius. It provides a localized magnetic field with a maximum intensity Bzc and shape as show in Fig 2 for compression of the particle beam towards the target.
  • the coil radius and field intensity Bzc determine the focal length of the beam.
  • the focal length is defined as the axial distance from the center of compression coil 46 to the point along the axis in which the particle beam crosses the axis.
  • the focusing field profile shown in Fig 9 can be used in some applications of the rotating wave accelerator.
  • the extractor field is gradually decreased (down-tapered) to allow gradual beam decompression wherein the particle beam's transverse velocity is converted into axial velocity. Beam decompressions is accompanied by an increase in the beam's radial distance from axis 102.
  • the particles motion is mostly axial with the beam spot rotating about the main axis 102 with a frequency equal to the radiation frequency ⁇ .
  • This kind of particle beam could be used for sterilization applications where goods such as food or medical supplies need to be radiated (scanned) over a wide area with an electron beam or x-rays.
  • the static axial magnetic field also serves a very important secondary function of focusing the electron beam, keeping it from spreading out due to the repulsive forces between the electrons.
  • Many accelerators have such a field for this purpose alone.
  • Magnetic field generator 26 can be implemented by conventional means such as solenoids, electro-magnets, super- conducting magnets and permanent magnets.
  • magnetic field generator 26 could be implemented by using a set of electro-magnet coils 26(l)-26(n) and compression coil 46. These coils can be equally dimensioned except compression coil 46 which can be made smaller.
  • magnetic field adjuster 110 can be comprised of a set of power supplies, each capable of providing a suitable amount of electrical current to each coil. (Each coil is powered by its own supply). If a large amount of current needs to be delivered to the coils, the supplies can be designed to deliver pulses of electrical current to minimize excessive cost of supplies and heating problems with the coils. For applications in which Bzm is large (>1.5 Tesla), magnetic field generator could be implemented by means of super-conducting techniques.
  • Figure 8 illustrates a typical result of beam acceleration simulations where the dynamics of an electron beam along the accelerating cavity 24 is shown.
  • the beam energy shown as a function of interaction length, is seen to gradually increase as the beam traverses accelerator cavity 24 ⁇ achieving a final energy of 6 MeV.
  • an electron beam with an initial energy of 5 keV and 100 mA current is injected into cylindrical cavity 24 holding a TM 1 10 rotating mode.
  • the cavity frequency is 2.85 GHz
  • the peak rf voltage inside cavity 24 is set to 7.5 MV
  • the cavity length is 15 cm and the cavity radius is 6.4 cm.
  • the rotating-wave accelerator 10 due to its compactness and relatively light weight should be suitable for medical and industrial applications.
  • the kind of beam produced by the rotating-wave accelerator 10 (as shown in Fig. 7) should be also useful for microwave applications where 200-500 keV electron beams are required.
  • the accelerator 10 should be able to provide 2-6 MeV electrons for radiotherapy machines.
  • the rotating-wave accelerator 10 should require less drive rf power, should be smaller and more efficient, and will require a smaller electron gun.
  • Figure 10 shows one example preferred embodiment in which the rotating wave accelerator 10 is provided within a tool casing 114.
  • the entire accelerator system 10 including rf generator 34 and pulser circuit 112 is assembled inside a tool 114.
  • rf generator 34, pulser circuit 112, and rotating wave accelerator 10 are all assembled inside tool casing 114.
  • Rotating wave accelerator 10 is comprised of an electron gun 20, cylindrical resonator 24 holding a TM 110 rotating mode, driving waveguides 28, 29, coupling holes 30, 32, target 44 and permanent magnet field generator 26.
  • Electron gun 20 is powered by pulser circuit 112 and produces a stream of low-energy electrons which are guided along the axis of cavity 24.
  • Pulser circuit 112 provides electrical power for rf source 34 and particle generating assembly 20.
  • Short electrical pulses are produced by pulser circuit 112 to power magnetron rf source 34 and particle generating gun 20.
  • Pulser circuit 112 can be implemented by means of energy storage elements or pulse forming networks and can be switched by means of thyratrons or solid-state switches such as MOSFETs or IGBTs. Electrical power is fed through tool casing 114 to the pulser by electrical cable 116.
  • Rf generator 34 is a compact microwave source such as a coaxial magnetron and is powered by pulser circuit 112 which produces microsecond-long electrical pulses. Magnetron source 34 produces short microsecond bursts of microwave power at a frequency equal to the frequency of operation of cavity 24.
  • Automatic frequency control system 118 keeps the magnetron 34 's frequency equal to the operational frequency of resonator 24. Frequency adjustment of magnetron 34 is achieved by servo-driven tuner 120.
  • a hybrid coupler 116 splits the microwave bursts coming from magnetron 34 into two equal-amplitude, 90°-phased signals which are subsequently sent to cavity 24 via waveguides 28, 29 through apertures 30, 32 to excite TM 110 rotating mode inside cavity 24.
  • Permanent magnet field generator 26 preferably provides a focusing magnetic field with a profile as shown in Fig 2.
  • Permanent magnet field generator 26 can be cylindrically shaped and made out of rare earth materials such as Samarium Cobalt to fit around cavity 24 and inside tool 114.
  • Cavity 24 is evacuated at low pressure (10 -9 Torr) and uses vacuum windows 48, 50 to preserve vacuum integrity.
  • Electron source 20 produces a stream of electrons that are injected into cavity 24.
  • particle beam assumes broadening radial trajectory (see Fig 7) as its is gradually accelerated to high energies.
  • the particle beam is compressed towards target 44.
  • target 44 could be a thin foil or an X- ray target. If tool 114 is to be used, for example, as electron beam welder, target 44 could be a suitable thin aluminum foil that allows the passage of the beam for utilization of the charged particles. In applications where photon radiation is sought, target could be made out of tungsten for the generation of X-ray radiation.
  • tool 1 14 includes automatic frequency control 118 means for adjusting the frequency of magnetron rf source 34.
  • Automatic frequency control senses the resonant frequency of accelerator cavity 24 and adjusts the frequency of magnetron rf source 34 via a servo-driven tuning plunger 120 in the magnetron 34.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Particle Accelerators (AREA)

Abstract

Accélérateur de faisceau électronique mettant en application un seul résonateur hyperfréquences maintenant un mode électromagnétique transversal magnétique à polarisation circulaire et un faisceau de particules chargées immergé dans un champ magnétique à focalisation axiale. L'effet combiné des champs hyperfréquences transversaux magnétiques et du champ magnétique axial confère au faisceau électronique une forme hélicoïdale et un mouvement de rotation permettant à la totalité du faisceau d'être accéléré en continu vers des énergies élevées de façon semblable au courant continu. L'utilisation d'un mode électromagnétique transversal magnétique à polarisation circulaire permet à la fréquence résonante d'être indépendante de la longueur du résonateur, ce qui permet à la longueur du résonateur d'être sélectionnée de manière à réaliser l'accélération souhaitée des particules. L'utilisation d'un mode transversal magnétique à onde rotative, TM110 permet à la fréquence de la cavité d'être indépendante de la longueur de la cavité et élimine le besoin de faisceaux multiples et de cavités courtes, tout en autorisant l'utilisation d'un faisceau à mouvement spiralé. Le faisceau électronique à onde rotative présente plusieurs mises en application possibles, par exemple, un générateur compact de faisceau électronique à énergie élevée pulsée à l'intérieur d'un boîtier d'outil.
PCT/US1997/018183 1996-10-18 1997-10-17 Accelerateur de faisceau electronique a onde rotative WO1998018300A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU48962/97A AU4896297A (en) 1996-10-18 1997-10-17 Rotating-wave electron beam accelerator

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US2878496P 1996-10-18 1996-10-18
US60/028,784 1996-10-18

Publications (2)

Publication Number Publication Date
WO1998018300A2 true WO1998018300A2 (fr) 1998-04-30
WO1998018300A3 WO1998018300A3 (fr) 1998-10-01

Family

ID=21845401

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1997/018183 WO1998018300A2 (fr) 1996-10-18 1997-10-17 Accelerateur de faisceau electronique a onde rotative

Country Status (3)

Country Link
US (1) US6060833A (fr)
AU (1) AU4896297A (fr)
WO (1) WO1998018300A2 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005013289A1 (fr) * 2003-07-31 2005-02-10 Vanier Stephane Procede pour modifier les trajectoires de particules a charge electrique
WO2006059816A1 (fr) * 2004-11-30 2006-06-08 Young-Min Shin Generateur d'ondes millimetriques/decimillimetriques
WO2013030804A3 (fr) * 2011-09-01 2013-07-11 Universidad Industrial De Santander Source compacte auto-résonnante de rayons x
EP2745654B1 (fr) * 2011-06-22 2015-07-29 Siemens Aktiengesellschaft Accélérateur de particules, ensemble d'accélérateur et procédé d'accélération de particules chargées

Families Citing this family (74)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100290829B1 (ko) * 1999-03-25 2001-05-15 정기형 전자빔 가속기를 이용한 산업용 엑스선원 및 전자선원
AU2001251222A1 (en) * 2000-03-31 2001-10-15 University Of Maryland, Baltimore Helical electron beam generating device and method of use
JP3464191B2 (ja) * 2000-06-05 2003-11-05 住友重機械工業株式会社 高周波共振器、及び、その製造方法
DE10041473B9 (de) * 2000-08-24 2004-10-14 Müller, Reinhold G., Prof.Dr. Vorrichtung zur Bestrahlung von Gewebe
CA2455663C (fr) * 2001-08-24 2008-02-26 Mitsubishi Heavy Industries, Ltd. Appareil de traitement radiologique
US6688116B1 (en) * 2002-12-20 2004-02-10 Physics & Technology, Llc Refrigerator electron beam ion trap-source
US7952304B2 (en) * 2003-08-27 2011-05-31 Zavadlsev Alexandre A Radiation system
US7206379B2 (en) * 2003-11-25 2007-04-17 General Electric Company RF accelerator for imaging applications
CN100420353C (zh) * 2004-04-19 2008-09-17 三菱电机株式会社 带电粒子束加速器、粒子束照射医疗系统及其运行方法
GB0416519D0 (en) * 2004-07-23 2004-08-25 Stenzel Security Ltd Electronic apparatus
US7586097B2 (en) * 2006-01-05 2009-09-08 Virgin Islands Microsystems, Inc. Switching micro-resonant structures using at least one director
US7791290B2 (en) * 2005-09-30 2010-09-07 Virgin Islands Microsystems, Inc. Ultra-small resonating charged particle beam modulator
US7626179B2 (en) * 2005-09-30 2009-12-01 Virgin Island Microsystems, Inc. Electron beam induced resonance
US7558374B2 (en) * 2004-10-29 2009-07-07 General Electric Co. System and method for generating X-rays
US7106004B1 (en) * 2004-12-20 2006-09-12 The United States Of America As Represented By The Secretary Of The Air Force All cavity magnetron axial extractor
US7368410B2 (en) * 2005-08-03 2008-05-06 Saudi Basic Industries Corporation Zeolite catalyst and method of preparing and use of zeolite catalyst
WO2007064358A2 (fr) * 2005-09-30 2007-06-07 Virgin Islands Microsystems, Inc. Structures et methodes de couplage de l'energie d'une onde electromagnetique
US20070152781A1 (en) * 2006-01-05 2007-07-05 Virgin Islands Microsystems, Inc. Switching micro-resonant structures by modulating a beam of charged particles
US7470920B2 (en) * 2006-01-05 2008-12-30 Virgin Islands Microsystems, Inc. Resonant structure-based display
US7619373B2 (en) * 2006-01-05 2009-11-17 Virgin Islands Microsystems, Inc. Selectable frequency light emitter
US7282776B2 (en) * 2006-02-09 2007-10-16 Virgin Islands Microsystems, Inc. Method and structure for coupling two microcircuits
US20070190794A1 (en) * 2006-02-10 2007-08-16 Virgin Islands Microsystems, Inc. Conductive polymers for the electroplating
US7443358B2 (en) 2006-02-28 2008-10-28 Virgin Island Microsystems, Inc. Integrated filter in antenna-based detector
US20070200071A1 (en) * 2006-02-28 2007-08-30 Virgin Islands Microsystems, Inc. Coupling output from a micro resonator to a plasmon transmission line
US20070243713A1 (en) * 2006-04-12 2007-10-18 Lam Research Corporation Apparatus and method for generating activated hydrogen for plasma stripping
US7646991B2 (en) * 2006-04-26 2010-01-12 Virgin Island Microsystems, Inc. Selectable frequency EMR emitter
US7876793B2 (en) * 2006-04-26 2011-01-25 Virgin Islands Microsystems, Inc. Micro free electron laser (FEL)
US20070252089A1 (en) * 2006-04-26 2007-11-01 Virgin Islands Microsystems, Inc. Charged particle acceleration apparatus and method
US7492868B2 (en) * 2006-04-26 2009-02-17 Virgin Islands Microsystems, Inc. Source of x-rays
US7359589B2 (en) * 2006-05-05 2008-04-15 Virgin Islands Microsystems, Inc. Coupling electromagnetic wave through microcircuit
US7728397B2 (en) * 2006-05-05 2010-06-01 Virgin Islands Microsystems, Inc. Coupled nano-resonating energy emitting structures
US7728702B2 (en) 2006-05-05 2010-06-01 Virgin Islands Microsystems, Inc. Shielding of integrated circuit package with high-permeability magnetic material
US20070258492A1 (en) * 2006-05-05 2007-11-08 Virgin Islands Microsystems, Inc. Light-emitting resonant structure driving raman laser
US7723698B2 (en) * 2006-05-05 2010-05-25 Virgin Islands Microsystems, Inc. Top metal layer shield for ultra-small resonant structures
US7583370B2 (en) * 2006-05-05 2009-09-01 Virgin Islands Microsystems, Inc. Resonant structures and methods for encoding signals into surface plasmons
US7557647B2 (en) * 2006-05-05 2009-07-07 Virgin Islands Microsystems, Inc. Heterodyne receiver using resonant structures
US7732786B2 (en) 2006-05-05 2010-06-08 Virgin Islands Microsystems, Inc. Coupling energy in a plasmon wave to an electron beam
US8188431B2 (en) 2006-05-05 2012-05-29 Jonathan Gorrell Integration of vacuum microelectronic device with integrated circuit
US7746532B2 (en) 2006-05-05 2010-06-29 Virgin Island Microsystems, Inc. Electro-optical switching system and method
US20070258720A1 (en) * 2006-05-05 2007-11-08 Virgin Islands Microsystems, Inc. Inter-chip optical communication
US7710040B2 (en) 2006-05-05 2010-05-04 Virgin Islands Microsystems, Inc. Single layer construction for ultra small devices
US7443577B2 (en) * 2006-05-05 2008-10-28 Virgin Islands Microsystems, Inc. Reflecting filtering cover
US7741934B2 (en) * 2006-05-05 2010-06-22 Virgin Islands Microsystems, Inc. Coupling a signal through a window
US7476907B2 (en) * 2006-05-05 2009-01-13 Virgin Island Microsystems, Inc. Plated multi-faceted reflector
US7554083B2 (en) * 2006-05-05 2009-06-30 Virgin Islands Microsystems, Inc. Integration of electromagnetic detector on integrated chip
US7718977B2 (en) 2006-05-05 2010-05-18 Virgin Island Microsystems, Inc. Stray charged particle removal device
US7342441B2 (en) * 2006-05-05 2008-03-11 Virgin Islands Microsystems, Inc. Heterodyne receiver array using resonant structures
US7436177B2 (en) * 2006-05-05 2008-10-14 Virgin Islands Microsystems, Inc. SEM test apparatus
US7442940B2 (en) * 2006-05-05 2008-10-28 Virgin Island Microsystems, Inc. Focal plane array incorporating ultra-small resonant structures
US7986113B2 (en) 2006-05-05 2011-07-26 Virgin Islands Microsystems, Inc. Selectable frequency light emitter
US7656094B2 (en) 2006-05-05 2010-02-02 Virgin Islands Microsystems, Inc. Electron accelerator for ultra-small resonant structures
US20070258675A1 (en) * 2006-05-05 2007-11-08 Virgin Islands Microsystems, Inc. Multiplexed optical communication between chips on a multi-chip module
US20070274365A1 (en) * 2006-05-26 2007-11-29 Virgin Islands Microsystems, Inc. Periodically complex resonant structures
US7884340B2 (en) * 2006-05-26 2011-02-08 Advanced Biomarker Technologies, Llc Low-volume biomarker generator
US7466085B2 (en) * 2007-04-17 2008-12-16 Advanced Biomarker Technologies, Llc Cyclotron having permanent magnets
US7679067B2 (en) 2006-05-26 2010-03-16 Virgin Island Microsystems, Inc. Receiver array using shared electron beam
US7655934B2 (en) * 2006-06-28 2010-02-02 Virgin Island Microsystems, Inc. Data on light bulb
US20080043910A1 (en) * 2006-08-15 2008-02-21 Tomotherapy Incorporated Method and apparatus for stabilizing an energy source in a radiation delivery device
US7450794B2 (en) * 2006-09-19 2008-11-11 Virgin Islands Microsystems, Inc. Microcircuit using electromagnetic wave routing
US7560716B2 (en) * 2006-09-22 2009-07-14 Virgin Islands Microsystems, Inc. Free electron oscillator
CN101163372B (zh) * 2006-10-11 2010-05-12 清华大学 多能倍频粒子加速器及其方法
US7659513B2 (en) * 2006-12-20 2010-02-09 Virgin Islands Microsystems, Inc. Low terahertz source and detector
US7990336B2 (en) 2007-06-19 2011-08-02 Virgin Islands Microsystems, Inc. Microwave coupled excitation of solid state resonant arrays
US7791053B2 (en) 2007-10-10 2010-09-07 Virgin Islands Microsystems, Inc. Depressed anode with plasmon-enabled devices such as ultra-small resonant structures
WO2011050306A1 (fr) * 2009-10-23 2011-04-28 Kaonetics Technologies, Inc. Dispositif, système et procédé pour générer des formes d'onde électromagnétiques, des particules subatomiques, des particules sensiblement dépourvues de charge et/ou des ondes magnétiques sensiblement exemptes de champ électrique
US9711253B2 (en) * 2010-11-28 2017-07-18 Tel Hashomer Medical Research Infrastructure And Services Ltd. Method and system for electron radiotherapy
WO2014123591A2 (fr) * 2012-10-17 2014-08-14 Cornell University Génération et accélération de particules chargées à l'aide de systèmes et de dispositifs compacts
CN107469240B (zh) 2013-02-26 2020-04-21 安科锐公司 多叶准直器和用于准直治疗放射束的系统
WO2015034949A1 (fr) * 2013-09-04 2015-03-12 Qmast Llc Amplificateurs klystron à faisceau feuille (sbk) avec une solénoïde enroulée pour un fonctionnement stable
KR20170062185A (ko) * 2015-11-27 2017-06-07 한국전기연구원 고출력 마그네트론에서의 자기장 형성 장치
WO2017192834A1 (fr) * 2016-05-04 2017-11-09 Cornell University Accélérateur de particules chargées à base de tranche, composants de tranche, procédés et applications
CN110658547A (zh) * 2019-10-17 2020-01-07 中国科学院上海高等研究院 测量束流能量的装置及方法
WO2023023050A1 (fr) * 2021-08-17 2023-02-23 Omega-P R&D, Inc. Accélérateur de haute puissance à résonance cyclotron compact pour électrons
CN114360842B (zh) * 2021-12-28 2022-11-22 中国人民解放军海军工程大学 一种应用于高功率微波源的轻型化周期性磁场线圈

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3916239A (en) * 1973-07-05 1975-10-28 Varian Associates High energy beam launching apparatus and method
US4253068A (en) * 1979-05-21 1981-02-24 Barnett Larry R Cyclotron maser using a spatially nonlinear electrostatic field
US4422045A (en) * 1981-03-20 1983-12-20 Barnett Larry R Barnetron microwave amplifiers and oscillators
US4641103A (en) * 1984-07-19 1987-02-03 John M. J. Madey Microwave electron gun
US4642591A (en) * 1984-11-16 1987-02-10 Murata Manufacturing Co., Ltd. TM-mode dielectric resonance apparatus
US4835446A (en) * 1987-09-23 1989-05-30 Cornell Research Foundation, Inc. High field gradient particle accelerator
US5073913A (en) * 1988-04-26 1991-12-17 Acctek Associates, Inc. Apparatus for acceleration and application of negative ions and electrons
US5280252A (en) * 1991-05-21 1994-01-18 Kabushiki Kaisha Kobe Seiko Sho Charged particle accelerator
US5361274A (en) * 1992-03-12 1994-11-01 Fusion Systems Corp. Microwave discharge device with TMNMO cavity
US5363054A (en) * 1992-02-27 1994-11-08 Massachusetts Institute Of Technology Double beam cyclotron maser
US5523659A (en) * 1994-08-18 1996-06-04 Swenson; Donald A. Radio frequency focused drift tube linear accelerator

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3450931A (en) * 1966-08-30 1969-06-17 Varian Associates Cyclotron motion linear accelerator
US3463959A (en) * 1967-05-25 1969-08-26 Varian Associates Charged particle accelerator apparatus including means for converting a rotating helical beam of charged particles having axial motion into a nonrotating beam of charged particles
US3398376A (en) * 1967-12-11 1968-08-20 Jay L. Hirshfield Relativistic electron cyclotron maser
US3965434A (en) * 1972-12-01 1976-06-22 Shm Nuclear Corporation Automatic frequency control system for driving a linear accelerator
US4143299A (en) * 1976-09-16 1979-03-06 The United States Of America As Represented By The Secretary Of The Navy Charged-particle beam acceleration in a converging waveguide

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3916239A (en) * 1973-07-05 1975-10-28 Varian Associates High energy beam launching apparatus and method
US4253068A (en) * 1979-05-21 1981-02-24 Barnett Larry R Cyclotron maser using a spatially nonlinear electrostatic field
US4422045A (en) * 1981-03-20 1983-12-20 Barnett Larry R Barnetron microwave amplifiers and oscillators
US4641103A (en) * 1984-07-19 1987-02-03 John M. J. Madey Microwave electron gun
US4642591A (en) * 1984-11-16 1987-02-10 Murata Manufacturing Co., Ltd. TM-mode dielectric resonance apparatus
US4835446A (en) * 1987-09-23 1989-05-30 Cornell Research Foundation, Inc. High field gradient particle accelerator
US5073913A (en) * 1988-04-26 1991-12-17 Acctek Associates, Inc. Apparatus for acceleration and application of negative ions and electrons
US5280252A (en) * 1991-05-21 1994-01-18 Kabushiki Kaisha Kobe Seiko Sho Charged particle accelerator
US5363054A (en) * 1992-02-27 1994-11-08 Massachusetts Institute Of Technology Double beam cyclotron maser
US5361274A (en) * 1992-03-12 1994-11-01 Fusion Systems Corp. Microwave discharge device with TMNMO cavity
US5523659A (en) * 1994-08-18 1996-06-04 Swenson; Donald A. Radio frequency focused drift tube linear accelerator

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005013289A1 (fr) * 2003-07-31 2005-02-10 Vanier Stephane Procede pour modifier les trajectoires de particules a charge electrique
WO2006059816A1 (fr) * 2004-11-30 2006-06-08 Young-Min Shin Generateur d'ondes millimetriques/decimillimetriques
EP2745654B1 (fr) * 2011-06-22 2015-07-29 Siemens Aktiengesellschaft Accélérateur de particules, ensemble d'accélérateur et procédé d'accélération de particules chargées
WO2013030804A3 (fr) * 2011-09-01 2013-07-11 Universidad Industrial De Santander Source compacte auto-résonnante de rayons x
EP2753155A4 (fr) * 2011-09-01 2016-01-20 Univ Ind De Santander Source compacte auto-résonnante de rayons x
US9666403B2 (en) 2011-09-01 2017-05-30 Universidad Industrial De Santander Compact self-resonant X-ray source

Also Published As

Publication number Publication date
WO1998018300A3 (fr) 1998-10-01
AU4896297A (en) 1998-05-15
US6060833A (en) 2000-05-09

Similar Documents

Publication Publication Date Title
US6060833A (en) Continuous rotating-wave electron beam accelerator
US3463959A (en) Charged particle accelerator apparatus including means for converting a rotating helical beam of charged particles having axial motion into a nonrotating beam of charged particles
US6914396B1 (en) Multi-stage cavity cyclotron resonance accelerator
US8203289B2 (en) Interleaving multi-energy x-ray energy operation of a standing wave linear accelerator using electronic switches
AU2006242025B2 (en) All-species ion accelerator and control method thereof
US4197510A (en) Isochronous cyclotron
US20080061718A1 (en) Standing-wave electron linear accelerator apparatus and methods
US6617810B2 (en) Multi-stage cavity cyclotron resonance accelerators
US4215291A (en) Collective particle accelerator
US3450931A (en) Cyclotron motion linear accelerator
Hirshfield et al. Multimegawatt cyclotron autoresonance accelerator
US2943265A (en) Electron cyclotron
US2953750A (en) Magnetic cable
Larionov et al. Design of multi-beam klystron in X-band
WO2002071817A1 (fr) Accelerateur a resonance cyclotron comportant des cavites a etages multiples
JP3027822B2 (ja) 荷電粒子ビームのマイクロバンチング方法及びそのための装置
RU2671915C2 (ru) Авторезонансный СВЧ-генератор
JPS58204443A (ja) コヒ−レント共振周波数マイクロ波放射を作る方法
JP2001052896A (ja) 粒子加速・蓄積装置
SU867279A1 (ru) Генератор синхротронного излучени непрерывного действи
RU1804661C (ru) Генератор рентгеновского излучени
JPH1041099A (ja) 折畳み軌道高周波電子加速器
Redhead Microtrons in Canada
EP1316246A1 (fr) Accelerateur a resonance cyclotron comportant des cavites a etages multiples
CN115175433A (zh) 一种螺线管束团禁闭模型及带电粒子束团电流压缩方法

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A2

Designated state(s): AL AM AT AU AZ BA BB BG BR BY CA CH CN CU CZ DE DK EE ES FI GB GE GH HU IL IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT UA UG US UZ VN YU ZW AM AZ BY KG KZ MD RU TJ TM

AL Designated countries for regional patents

Kind code of ref document: A2

Designated state(s): GH KE LS MW SD SZ UG ZW AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: CA